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Successful in the Past Prepared for the Future

A review of the performance of Polybutene pressure piping systems in meeting the needs of sustainable building regulations.

www.pbpsa.com An Introduction to Polybutene

Polybutylene was discovered over 50 years ago. Its introduction into pressure piping applications started in the mid 1960s. Since then continuous research and development has resulted in optimised material characteristics, improved manufacturing technology and sophisticated designs of piping systems components.

Piping systems made from Polybutylene demonstrate exceptional performance in a variety of demanding long-term applications and have become a vital PB-1 molecular structure part of modern energy-efficient and ecologically acceptable building technology resulting in a booming growth rate for the product in recent years.

www.pbpsa.com 2/12 Performance Characteristics

Polybutylene exhibits a unique morphology and Figure 2: Creep behaviour of polyolefins at crystallisation behaviour which, combined with careful room temp (8 MPa) control of molecular parameters, gives Polybutylene a profile of properties unrivalled in piping systems manufacture ( Figure 1 ).

Figure 1: Comparison of Polymers used in Plumbing

PB-1 PP-R PE-X PVC-C

Impact Toughness ••• •• ••• •

Chemical Resistance ••• ••• ••• •••

Flexibility •••• •• ••• •

Creep Resistance •••• ••• ••• •••

Thermal Pressure Resistance •••• •• ••• •••

Weldability •••• •••• • ••

Key •••• ••• •• • Excellent Good Fair Poor In terms of flexibility, expressed in Figure 3 as an elastic modulus, Polybutylene is clearly the product The most important of these properties which sets of choice. Flexibility is a key factor because it Polybutylene apart from competitive products is the enables easier and faster installation. The ease of combination of high flexibility and outstanding cabling pipe through drilled holes and threading resistance to internal pressure creep resistance over through confined spaces, combined with long pipe a wide range of hot and cold water temperatures. runs and a consequent reduction in the number of fittings required, are all factors which contribute to All polyolefinic materials tend to creep when exposed to the speed of installation and associated reduction continually applied stress over a long period of time. in costs. In addition, Polybutylene offers many This cold flow behaviour can be suppressed by creating benefits in service to the consumer. a three dimensional network in the polymer structure e.g. by physical or chemical cross linking as is the case in the manufacture of cross-linked Polyethylene (PEX). Figure 3: Flexural Elasticity Modulus (MPa) Method ISO 178 However Polybutylene displays superior inherent creep resistance ( Figure 2 ) without the application of any PVC-C PP-R PE-RT PEX PB-1 additional cross linking, copolymerisation or compounding modification. In its simplest homopolymer 3500 800 550-650 600 450 form, its property profile is ideal for satisfying the demands of pressure piping applications. (PE-RT – Raised Temperature Resistance polyethylene)

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Its inert chemical properties and apolar nature hinder limescale deposition thus ensuring long-term efficiency in water heating and circulation. Its resistance to freezing temperatures combined with its elastic properties ensures that when water freezes in the pipe the ensuing expansion is accommodated by a temporary increase in the pipe wall diameter, minimising the possibility of bursting by sub-zero temperatures during spells of cold weather.

Due to the low elastic modulus, low density and low thermal expansion, polybutylene pipes have superior acoustic behaviour with no water hammer or other noise problems ( Figure 5 ).

Figure 5: Sound velocity in Materials

Density Elastic Modulus Sound Velocity (g/cm3) (MPa) (m/s)

Copper 7.2 110,000 3,900 It is designed to meet stringent organoleptic and food contact approvals ( Figure 4 ) and hence is well suited PB-1 0.94 450 620 for drinking water applications.

CPVC 1.56 3,500 2,350 Figure 4: European Approvals

1 UK BSI BS 7291 PEX 0.95 600 800 2 UK BBA 3 UK WRAS Water Quality Approval UK Soft Rubber 0.90 90 320 4 Germany DVGW W534/W544 5 Germany DIN DIN 16968/DIN 16969 6 Germany KTW Water Quality Approval Germany Such excellent acoustic performance was a contributory 7 Netherlands KIWA BRL K 536 factor in Polybutylene being the material of choice for 8 Netherlands KOMO (Heating) BRL 5604/5 the renovation of London’s Royal Albert Hall water 9 Netherlands ATA Water Quality Approval Netherlands piping system. 10 Poland Polska Instal TIN – BS 7291 & ISO 158756 11 Hungary EMI ISO 15876 Finally, as an essentially ‘pure’ highly isotactic 12 Bulgaria Executive Agency BS EN ISO 15876 homopolymer, Polybutylene is more easily Cert & Testing specified than some alternative materials to 13 Austria ÖVGW Önorm ISO 15876 consistently achieve quality performance, and when 14 Spain AENOR UNE EN ISO 15876 necessary, is easily recyclable. 15 Portugal LNEC ISO 15876 16 France CSTB Avis Technique 17 Croatia DVGW W534/W544 18 Switzerland SVGW ISO 15876 19 Turkey TSE 20 Denmark ETA ISO 15876

www.pbpsa.com 4/12 Pipe Performance Comparison

The resistance of pipes to Figure 6: Comparison of reference lines @ 70˚C for PB-1, PEX, PP-R and PE-RT deformation and burst is determined by testing to international and national standards. Three piping systems standards exist in parallel, namely ISO 15876 for Polybutylene, ISO 15875 for PEX, and ISO 15874 for Polypropylene. The data presented in these standards provides a useful means of comparison between the performance of these three alternative plastics materials (Figure 6 ). A comparison with PE-RT is also included but since no published ISO standard exists to date the data presented was obtained from ISO/DIS 24033.

The data provided can then be used to calculate the maximum permitted hoop stress for hot water transportation according to a defined set of conditions referred to as temperature classes. These temperature classes are compiled to reflect the likely cross-section of service conditions for a 50-year period for a range of different Figure 7: Classification of Service Conditions for 50 years CEN/ISO Classes heating and water supply applications. These internationally Service Conditions accepted temperature classes are stipulated in ISO standard 10508 and referred to in the systems Class Application Normal Maximum Malfunction standards for plastic piping systems Temp Time Temp Time Temp Time (Figure 7 ). ˚C years ˚C years ˚C hours

1 Hot Water Supply @ 60˚C 60 49 80 1 95 100

2 Hot Water Supply @ 70˚C 70 49 80 1 95 100

Underfloor Heating 40 20 4 70 2.5 100 100 Low Temp. Heating Systems 60 25

High Temp. 60 25 5 90 1 100 100 Heating Systems 80 10

www.pbpsa.com 5/12 Pipe Performance Comparison

By employing standardised Figure 8: Maximum allowable Hoop Stress (MPa) (Design Stress) dimensional criteria presented in ISO of Polyolefin Pipes for Hot Water Transportation 10508, it is possible to calculate the PB-1 PEX PE-RT PP-R maximum allowable hoop stress of the alternative polyolefin pipes for the Raised Cross-linked Temperature Polypropylene various applicational temperature Polybutene-1 Random- Temperature Class (ISO 15876-2) Polyethylene Resistance Copolymer (ISO 15875-2) Polyethylene (ISO 15874-2) classes. These calculations result in (ISO/DIS 22391-2) the comparisons presented in Figure 8 where it is shown that the maximum 1 (HWS 60˚C) 5.73 3.85 3.30 3.09 allowable hoop stress or design stress for Polybutylene pipes is some 35% higher than for cross-linked 2 (HWS 70˚C) 5.06 3.54 2.70 2.13 polyethylene PEX pipes, 45% higher 4 (UFH and low than for Polypropylene PP-R pipes, 5.46 4.00 3.26 3.30 and more than 50% higher than for temperature radiators) non cross-linked PE-RT pipes. 5 (High temperature 4.31 3.24 2.4 1.90 radiators) This effectively means that at equivalent thickness, Polybutylene pipes offer a significant margin in Figure 9: 50 Years life (70˚C curve) including design factor design factor over these alternative plastic materials when pipe standards PB-1 PEX PP-R PVC-C specify equivalent wall thickness. Pipe dimension 40mm 3.7 5.5 6.7/8.0 4.5 OD x thickness (mm) However for the maximum allowable hoop stress, we can calculate a minimum allowable wall thickness. ID (Inner diameter) (mm) 32.6 29.0 26.6/24.0 31.0 These calculations show that Polybutylene pipes can be produced 2 with a significantly reduced wall Pipe inner surface (mm ) 834 660 555/462 754 thickness when compared with alternative competitive materials PN 20/ Pressure rating PN 16 PN 20 PN 25 dependent on applicational standards PN 25 limitations. Lower wall thickness means, in addition to material savings, a larger internal bore for a given external pipe diameter, resulting in reduced head pressure loss and lower flow speeds to deliver a fixed Flow speed [m /s] . 2.4 3.0 3.6/4.4 2.7 volume of water. Figure 9 illustrates at V = 2.0 l/s the benefits of using Polybutylene in comparison with competitive materials Loss of pressure [mbar] 49.5/81.3 . 18.4 32.5 23.6 in a 40 mm diameter pipe for a at V = 2.0 l/s (SVGW/DVGW) 50-year life expectancy at a continuous operating temperature Ratio of Linear 1 1.44 1.66 1.57 of 70˚C including design factors. pipe weight

www.pbpsa.com 6/12 Sustainability and Environmental Compatibility

The issues of sustainability, energy efficiency and The plant was only commissioned in 2003 and environmental impact have come to the fore over therefore had to satisfy the latest Dutch government the last few years. The legislative pressure which regulations on environmental impact. It is both ISO affects the construction industry is being driven by 9001 and ISO 14001 certified (Figure 11 ). the imminent EU ‘Energy Performance in Buildings Directive’ which has already had a profound Figure 11: DNV Management System Certificate influence on member governments who have independently introduced their own new building regulations. The guidelines for ‘sustainable buildings’ demand that the impact on the environment and the associated consumption of energy costs and resources is minimised throughout all phases of the life cycle of a building from planning to demolition.

With specific regard to the choice of a hot and cold water piping system for new building projects, Polybutylene piping systems have clear benefits over competitive products.

Manufacturing Polybutylene is a derivative of the refining of crude oil. The monomer butene-1 is obtained from the olefins fraction of the cracking process, together with ethylene and propylene. Polybutylene is produced by Energy consumption of the manufacturing process is the polymerisation of butene-1 using a very high also extremely low in terms of consumption per unit yield, low temperature catalyst system. This, together finished product, and compares favourably with the with the fact that polymerisation takes place in raw material production of competitive piping solution in the monomer, means there is no systems. When compared with the raw material of requirement to purify the resulting polymer. The traditional metal piping, Polybutylene shows clear unpolymerised monomer is simply recovered and advantages in terms of kilograms oil equivalent per recycled within the process. Polybutylene is produced litre of material ( Figure 12 ). in Europe solely by Basell at their new production facility in The Netherlands ( Figure 10 ). Figure 12: Kilograms Oil – Equivalent/Litre Material

Figure 10: Polybutylene Manufacturing plant, Moerdijk, The Netherlands

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Pipe Manufacture All plastic pipes are manufactured via an extrusion process which involves raising the temperature of the raw material above its melting point, compressing the melted plastic through a die to form the pipe which is then cooled and coiled. Some plastics then require a second processing step to produce the finished product. Polybutylene however is inherently fit for purpose without modification or secondary processing with the additional advantage that any uncontaminated off-specification production can be ground and recycled within the process. Raw material waste is therefore negligible.

Transportation The Polybutylene manufacturing plant is situated at Moerdijk in The Netherlands close to the oil refinery and port facilities at Rotterdam. Moerdijk is also close to the epicentre of the Polybutylene piping systems business in Europe with the major pipe producers situated in The Netherlands, Switzerland, Germany, the UK and Austria (Figure 13 ).

Butene-1 feedstock is provided from European John Guest Ltd. Thermaflex International Holding b.v. sources in the vicinity of the plant. Polybutylene raw material is then transported by road either in LyondellBasell Industries n.v. PB-1 manufacturing plant bulk tanker consignments or semi-bulk recyclable board containers. The finished product pipe is also Thermaflex-Flexalen Rohr- und Isoliersysteme GmbH transported by road to the installation site. HakaGerodur AG

The majority of the Polybutylene piping systems Nueva Terrain S.L. business is nationally or European based and hence transportation distances are relatively short. Clearly it is not possible to provide meaningful calculations on transportation energy consumption or environmental impact, but we feel confident that the Polybutylene piping systems business compares favourably with all competitive systems.

www.pbpsa.com 8/12 Sustainability and Environmental Compatibility

Installations Figure 15: Standardised Comparison (VENOB) of Energy Efficiency – The Technical University of Berlin Various Pipe Materials Impact on the Environment – Emissions in Soil have conducted an energy efficiency and environmental impact analysis on hot and cold water pressurised piping systems. The study made a comparison of the total energy consumption for the production and installation of a piping system for a multiple dwelling with 16 apartments using a number of competitive metal and plastic systems. Due principally to their lighter weight, plastics materials had a distinct advantage over metal pipes, but the Polybutylene piping system proved to be 50% lower in total energy consumption than the other plastics systems included in the study. This was due to its superior internal pressure performance, permitting the utilisation of pipes with smaller wall thickness ( Figure 14 ). Figure 16: Standardised Comparison (VENOB) of Figure 14: Energy equivalent Value of the Complete Various Pipe Materials Impact on the Environment – Piping System for a 16 Family Housing Complex Emissions in Water

Environmental Impact of Emissions – To provide a comparative analysis of emissions into soil, air and Figure 17: Standardised Comparison (VENOB) of water the T.U. Berlin study developed a standardised Various Pipe Materials Impact on the Environment – comparison method, referred to as VENOB Emissions in Air (Vergleichende Normierende Bewertung). This method allows a simplified and straightforward interpretation of the emissions data. Single emissions are recorded, standardised and then summarised in three individual and independent parameters: emissions into soil; emissions into water; and emissions into air. The lowest specific value of the six pipe materials compared was set to 1.0 and the other values were then calculated relative to this lowest value. The figures presented illustrate the results and show that in all three emissions, Polybutylene piping systems have the least environmental impact ( Figures 15-17).

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Site Safety – Health and safety are key concerns in all Recycling construction projects. The ease of installation of Recycling is undertaken at each stage in the Polybutylene piping systems contributes considerably manufacture and utilisation of Polybutylene piping to good site safety. As previously discussed, the systems. However, the processes for producing the flexibility of Polybutylene pipes means that it can be raw material, for manufacturing the pipe, and for the easily cabled through holes and tight spaces installation of the piping system into its end use minimising the need for cutting and jointing. Many application are all designed to maximise the use of installations can be carried out without pre-measuring the raw material with little waste. since it is easy to cut in situ. Since no bending tools are required, a complete pipework installation can be The Polybutylene production plant is a state-of-the-art completed requiring only a pair of cutters. No naked design, commissioned in 2003, and as previously flame heating is required to make reliable watertight described, recycles butene-1 monomer within the process. joints. For larger bore pipes, pre-fabricated socket fusion and/or in situ electrofusion systems can be During the extrusion of Polybutylene into pipe, the installed using computerised easy-to-use electrofusion molecular structure of the polymer remains essentially welding techniques. No solders, fluxes, greases or unchanged during the extrusion process. This is in solvents are used with Polybutylene systems. contrast to some alternative materials whose structure Portable Electrofusion Welding Apparatus is radically altered by the addition of chemicals or post-extrusion treatment and therefore unsuitable for in-line recycling.

The manufacturing processes for both the extrusion of pipe and the injection moulding of fittings are managed to minimise waste. ISO standard 15876 specifies that a manufacturer’s own clean production waste can be re-granulated and re-used as long as it is the same grade of material to which it is being added, and that no other re-work is permissible. Any other contaminated or off-specification production waste can also be re-granulated and used in the production of ‘lower’ specification products. Polybutylene piping systems are also non-conductive, providing a safer system with Due to its flexibility and other versatile characteristics, minimum earthing requirements. the installation of Polybutylene piping systems also generates very little waste. Smaller diameter pipe can Pre-fabricating using electrofusion welding be delivered to site in coils of typically 25 – 400 metres in length and cut in situ. Larger diameter joints are often pre-fabricated and delivered to site in sections, thus avoiding any on-site off-cuts.

Theoretically, after decades of service, Polybutylene pipe is expected to retain its original polyolefin structure and if recovered, could be recycled by standard plastics conversion techniques into ‘lower’ specification products.

www.pbpsa.com 10 /12 Prepared for the Future

Polybutylene piping systems have been successfully Compared to alternative materials, the environmental used in pipe applications in Europe for almost 40 compatibility of Polybutylene pipes rates very highly years. Installations in district and underfloor heating as illustrated by the data generated at the Technical systems in Austria and Germany in the early 1970s are University of Berlin. We can rightly claim that still in trouble-free operation today. Perhaps the most Polybutylene piping systems are clearly the preferred noteworthy success of Polybutylene pipes to date has choice in this respect. been their use in the Vienna Geothermal project, which since 1974 has utilised very aggressive With the advent of new building regulations and geothermal water as the heating medium and is still directives focused on the ecological factors of operating today at a constant temperature of 54°C energy efficiency and environmental compatibility, and a pressure of 10 bar. In the same application, we are confident that the versatile characteristics metal pipes had previously proved totally unsuitable and exceptional long-term performance of due to rapid corrosion problems. Polybutylene piping systems will meet the need of architects, specifiers and systems designers in The sustainability of Polybutylene piping systems is fulfilling these new government standards. therefore a proven case based on actual end-use performance experience. Since these first installations, Polybutylene piping systems suppliers provide advances in both material technology and production complete systems including pipes, fittings and processes, combined with the introduction of accessories, together with training on their installation, stringent standards have furthered the performance thus performance integrity can be guaranteed. and reliability of Polybutylene piping systems. International standards protocols now specify a The Product Warranties vary slightly according to minimum performance for Polybutylene hot water the manufacturer; however warranties of up to 50 pipes of 70˚C, 10 bar pressure for 50 years. years are available for Polybutylene piping systems, reflecting their proven long-term performance even Polybutylene piping being installed over 30 years ago in the most stringent applications.

www.pbpsa.com 11 /12 PBPSA | Polybutene Piping Systems Association

The Polybutene Piping Systems Association (PBPSA) is an international association of market leading companies committed to the use of the thermoplastic material, Polybutene-1 (PB-1) for the manufacture of piping systems. Also known as polybutylene, PB-1 is used worldwide in applications including piping systems for large-scale building projects, district energy networks, heating and cooling, and plumbing installations.

Polybutene Piping Systems Association Postfach 3377 [email protected] 8021 Zürich www.pbpsa.com SWITZERLAND

PBPSA Members

www.hakagerodur.ch

www.johnguest.com

www.lyondellbasell.com

www.nuevaterrain.com

www.thermaflex.com

© 2016 – Polybutene Piping Systems Association (PBPSA)

Before using a product made from Polybutene-1 users should make their own independent determination that the product is suitable for the intended use and can be used safely and legally. Polybutene-1 may not be used in the manufacture of any US FDA Class III Medical Device or Health Canada Class IV Medical Device and may not be used in the manufacture of any US FDA Class II Medical Device or Health Canada Class II or Class III Medical Device without the prior written approval by Seller of each specific product or application. Polybutene-1 is not sold by PBPSA members for use in pipe applications intended for use in North America, and those parties require their customers or distributors not to sell products made from PB-1 into pipe applications for North America.

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